Chelation of the Collagen Peptide of Seabass (Lates calcarifer) Scales with Calcium and Its Product Development
Round 1
Reviewer 1 Report
Please refer to attachment.
Comments for author File: 
Comments.pdf
Author Response
Response
Thank you for the thoroughly reviewing and offering many excellent comments and suggestions. We offer a response for each point of reviewing and revise the manuscript accordingly. All revised parts in the manuscript are labelled in red. Following is our response.
Reviewer 1:
- Abstract: blackcurrant or berry-grape seeds. The whole manuscript. Is it berry-grape seeds or grape seed only? As in the Result and Discussion section there were separated between blackcurrant and grape seed.
Response: Thank you for this correction. It was the extract of grape seed mixed with berry juice. We revised to berry-grape seed throughout the manuscript.
- when oxalate, phytate, tennis, and phosphate. What is tennis?
Response: Thank you for this correction. We correct to the right term, tannin.
- provided by a local company, please provide the name, province of the company.
Response: Thank you for the suggestion. We revised to “The fish scales of seabass were provided by Mammafisch Co. (Kaohsiung, Taiwan).”
- FTIR: room temperature Please specify the temperature
Response: Thank you for the suggestion. FTIR was conducted in a temperature-controlled room and the temperature was 25-28°C. We have revised to “The frequency of FTIR (FT-730, Horiba, Tokyo, Japan) was set from 400 to 4000 cm-1 and tests were conducted in a temperature-controlled room ranging 25-28°C.”
- pH: … was used as the control. …was used as a control.
Response: we revise accordingly.
- One hundred μL One hundred microlitres
Response: we revise accordingly.
- ..whose results… ..which results…
Response: we revise accordingly.
- .. decreased greatly from the one. One is refer to what?
Response: Thank you for the suggestion. We revise to” The molecular weight of SBSCP ranged from 307-760 Da, which decreased greatly from the molecular weight (10 kDa) before hydrolyzation.
- Sensory evaluation: calendula scored the lowest points. Please state the possibilities why adding this material would score the lowest points.
Response: Thank you for the suggestion. We revise to “These results could result from the weedy flavor of calendula. Additionally, blackcurrant and berry-grape seed possess sweeter flavor and stronger aroma.”
- Table 2: Non, Non is referred to what sample?
Response: Thank you for the correction. We add a note “Non refers to SBSCP-Ca without adding plant extract.”
- Sensory: .. and flavonols and flavanols
Response: Thank you for the correction. We correct it accordingly.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The manuscript of Yan et al. presents an original and interesting work about the potential use of scales of seabass to improve calcium absorption in the human organism.
In general, the manuscript fulfills the requirements established by Sustainability journal. The Introduction section briefly describes the state of the art of the topic as well as it clearly indicates the objectives of the work and its significance. The Materials and methods part is well-described and explained, with enough details to be reproducible. The study presents interesting results which are well discussed and could be a good starting point for further research works. The Figures and Tables are useful for the interpretations of the results. The references are properly presented as they are identified with numbers in square brackets in the text.
Although the manuscript is well-written and could be worthy of publication, some changes must be made. Suggestions and comments to improve the quality of the manuscript are the following:
1. A cover letter must have been included in the submission of the manuscript to explain the reasons for why the work should be published.
2. The title should be more concise, and it must be adjusted to the content of the manuscript.
3. To enrich the content of the manuscript, authors must include a paragraph indicating the potential health benefits of using scales of seabass with calcium chelated (addressing both health and sustainability aspects) as well as the potential applications in food/pharmaceutical industries.
4. Authors must include a paragraph explaining the most important limitations of the study.
Author Response
Response
Thank you for the thoroughly reviewing and offering many excellent comments and suggestions. We offer a response for each point of reviewing and revise the manuscript accordingly. All revised parts in the manuscript are labelled in red. Following is our response.
Reviewer 2:
- A cover letter must have been included in the submission of the manuscript to explain the reasons for why the work should be published.
Response: Thank you for this suggestion. We have revised the cover letter to emphasize this manuscript fitting the scope of this journal and special issue.
- The title should be more concise, and it must be adjusted to the content of the manuscript.
Response: Thank you for this suggestion. We have revised the title as “Chelation of the collagen peptide of seabass (Lates calcarifer) scales with calcium and its product development”
- To enrich the content of the manuscript, authors must include a paragraph indicating the potential health benefits of using scales of seabass with calcium chelated (addressing both health and sustainability aspects) as well as the potential applications in food/pharmaceutical industries.
Response: Thank you for this suggestion. We have added a paragraph, “As aforementioned, collagen itself possesses several healthy functions, particularly for joint and skin care. In addition, chelating with calcium elevates the absorption rate of calcium. This study successfully obtained a collagen-calcium product, which showed high sensory scores and demonstrated excellent stability during digestion test and storage. Thus, this chelated product possesses highly potential value for the market of functional food. Furthermore, the collagen is obtained from fish scales, a by-product of fish processing. It fits the principle of a sustainable economy, which emphasizes on reutilizing by-product and reducing waste.”
- Authors must include a paragraph explaining the most important limitations of the study.
Response: Thank you for this suggestion. We have added a paragraph, “The results clearly showed that the products possessed commercial potential. However, the fishy odor is the main obstacle for consumer acceptance. Plant extracts are suitable substances to neutralize the fishy odor but only the ones with strong flavors are appropriate. In this study, three plant extracts were tested but only the extracts of blackcurrant and berry-grape seed were suitable. Though calendula is rich in lutein and popular in the functional food market, its weak flavor was unable to mask the fishy odor effectively. Coupling with granulation, the percentage of collagen reduces furthermore. Thus, other types of products, such as a jelly-like, processing method or spray drying, should be considered for commercialization.”
Author Response File: Author Response.docx
Reviewer 3 Report
I read carefully the manuscript entitled “Studies on the collagen peptide of seabass (Lates calcarifer) scales chelated with calcium and their product developments”. The following major revisions are required before this manuscript can be accepted.
1). Section 3.1. Molecular weight of SBSCP. The molecular weight distribution data was not presented in the manuscript. It should have size-exclusion chromatogram data. Please supplement the figure.
2). Section 3.3. FT-IR analyses. “–CO” might be “C=O”?
3). Section 2.6.3 and Section 3.5. The “In vitro simulation of gastrointestinal digestion of SBSCP-Ca” in the manuscript was independent of gastric digestion and intestinal digestion at different time. However, in actual human digestion, gastric digestion is followed by intestinal digestion. What about the stability of SBSCP-Ca after the simulation of actual human digestion?
Author Response
Response
Thank you for the thoroughly reviewing and offering many excellent comments and suggestions. We offer a response for each point of reviewing and revise the manuscript accordingly. All revised parts in the manuscript are labelled in red. Following is our response.
Reviewer 3:
1). Section 3.1. Molecular weight of SBSCP. The molecular weight distribution data was not presented in the manuscript. It should have size-exclusion chromatogram data. Please supplement the figure.
Response: Thank you for the comment. The molecular weight was very similar to our previous study (Reference 8, Chou, et al., 2020). We have added the data in the supplement data, S2. Additionally, we revised the description as “The molecular weight of SBSCP ranged from 307-760 Da, which decreased greatly from the molecular weight (10 kDa) before hydrolyzation (S1). The decrease of molecular weight after hydrolyzation and the range of molecular weight were similar with our previous study, which also used seabass scales as the collagen source [8] and other studies using mullet, milk fish, and tilapia [14, 32].”
2). Section 3.3. FT-IR analyses. “–CO” might be “C=O”?
Response: Thank you for the correction. We revise to “C=O” accordingly.
3). Section 2.6.3 and Section 3.5. The “In vitro simulation of gastrointestinal digestion of SBSCP-Ca” in the manuscript was independent of gastric digestion and intestinal digestion at different time. However, in actual human digestion, gastric digestion is followed by intestinal digestion. What about the stability of SBSCP-Ca after the simulation of actual human digestion?
Response: Thank you for the comment. Previous studies demonstrated around 76-80% and 70% retention rates for calcium [19, 40] and ferrous [17], respectively. Our study was designed to understand which section of digestion tract affect the stability of chelated products more. We revised the description in Section 3.5. as “These results contrasted with a previous study [39], in which cattle bone collagen chelated with calcium showed much higher stability in the simulated intestinal digestion than the gastric one. Zhang et al [39] proposed that calcium was released more easily in the acidic condition of the gastric environment than in the slightly alkaline intestinal condition since the chelated bone collagen also demonstrated higher stability in alkaline conditions. However, SBSCP-Ca showed higher stability in acidic condition in this study. Its difference could due to the different nature of cattle bone collagen and fish scale collagen because other studies showed the chelated products by using collagen from fishes [19, 17, 40] had higher stability in acidic condition. As for continuously digestion stability, those studies demonstrated around 76-80% and 70% retention rates for calcium [19, 40] and ferrous [17], respectively. Our study showed the individual stability of the chelated product of fish collagen-calcium to understand which section of digestion tract affecting the stability of chelated products more. Based on the results, the fish collagen chelated products were more stable in gastric condition than intestinal condition.”
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
Dear authors,
After carefully reviewing the last version of the manuscript, I agree this work is worthy of publication in the present form. Authors have followed the suggestions and comments and the quality of the manuscript has increased.
Author Response
Thank you for the thoroughly reviewing and valuable comments.
